Reactive coil.



0. P. STEINMETZ. REACTIVB HOI APPLICATION FILED MAYi9,1906.

'Fig. I.

Fig. '2. v Fig. 3.

Witnesses:

Inventor Charles F. Steinmetz,

PATENTED APR. 7, 1908.

Urrirnn STATES PATENT oFF oE.

CHARLES P. STEINMETZ, OF SOHENECTADY, NEW YORK, ASSIGNOB TC GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

nnnorivn ooIL.

' To all whom it may concern:

at Schenectady, county ofschen ectady, State I of NewYork, have invented certain new and useful Im rovements in Reactive Coils of l which the following is a specification.

This invention relates to a mode of controlling the discharge of reactive/coils, and more especially those used with mercury va or I'ectiliers.

f a reactive coil is energized by a current, say a direct current, and. then the circuit is broken, the current in the reactive coil will fall oil in an exponential curve which varies with the reactance and the resistance of the circuit. The voltage induced by the 112- active coil will follow the same curve. The inducedc'urrent is at a maximum at the beginnin and dies out gradually. In order (l the current over for a period of any length, an extremely high reactance is necessary. :In' many cases, however, and especially i1 mercury arc lamps or rectifiers for alternating currents, it is desirable to use a reactive coil oi as small dimensions as.

possible and having the least possible amount of reactance, but yet obtain'a discharge curve extending over a long period of time. It is not necessary that the current should be high in the beginning of the dischar e, but on the contrary it is desirable that the rate of dro should be small, .so that during the end oi the discharge, "when the next half wave is to be started, a considerable current will still be flowing and maintaining proper,

' excitation of themercury arc device.

I have discovered that by combining with the reactive coil a short-circuited secondary coil of fairly good mutual inductance with the main or reactive coil, but stilthaving some self-inductive reactance against the 7 main coil--that is, so thatthere is some stray field between the main andsecondary coils-- the discharge curve of the main coil is entirely changed. Since the same number of lines of magnetic force out the primary coil during the discharge. when the secondary coil is used as whenit is absent, the total elcctromotive force induced in the primary or ,main coil, and consequently the total )rimary current, is the'same in both cases. ut thecmutual reactance of the two coils causes: a lowering of the primary current Specification r Letters Patent. Application filed May 19, 1906. Serial Ne. 317,748.

:somewhat rapidly and Patented April 7, 1908.

In the accompanying drawing, Figure 1] is a diagrammatic representation of a mercury arc rectifier equipped WIlJlI my improved reactance coils; Fig. 2 is a diagram of the coordinated curve of nduced current when no secondary coil is used; and Fig. 3 is a dia grain showing the effect of the secondary coil. T

The alternating current mains 1,2, are connected with the two anodes-3 4 projecting into the envelop 5 in which the mercury are is maintained. The two reactance co 6 7 are connected in series across said mains,

and the direct current conductor and load 8 are connected from a point between them to the cathode 9. Surrounding each reactance coil is a closed secondary coil 10, 11. The drawing is merely an illustration of one mode of utilizing the invention. It is to beunderstood that reactances of the special tyne described may be introduced in the. anode leads or in the load circuit in the same way and for the same, urpose that simple reactive coils have hereto 'ore been used. I

When thesource of electromotive force is withdrawn from a simple reactive coil, either by breaking a direct current .or bythe 'subv sidence of the wave of an alternating current, the voltage and current thereupon induced falls olli'rom thli initial .value, at first an exponential curve 2, Fig. 2; the controlling elements being llhe-reactance and the resistance of the circuit. But Iwhen the closed secondary coil is added, the primary current at first falls oil very rapidly, at a rate ap roximately corresponding: to the selfim uctive reactance of the stray field between the primary coil and the secondary coil. At the same time, there appears in the secondary coil a current which rises at first very rapidly, and then more slowly, reaches a maximum, and then graduall drops; As' soon as this rise of current in t e secondar coil slows up'an'd ceases, the fall ,of the pmthen more slowly, in I niary current also becomes lessrapid andirl timatcly very slow so that the primary current 18 maintained over a period much greater than is the case without the 'sceondarycoil.

This interaction of the two coils isshown'in Fig. 3, where the curve 13 represents the rise and fall of the secondary current, audit-he curve 14 represents the changed primary device, oi" reactive coil, and means for equalicing the diechm'ge of said coil.

4. The combinationwith a. vapor electric device, of a reactive coil for maintaining said device active, and a secondary coil in inductive relation to said reactive coil.

5. The combination with a vapor electric device, of a reactive coil, and a closed secondcry coil in inductivereletion to said reactive coil.

6. The combination with a. veporelectric device having a plurality of anodes and a cathode, of reactive coils connected to said anodes, and closed secondary coils in inductive relation to said reactive coils toprolong the period of discharge of said reactive coils.

7. The combination of a vapor electric device, reactive means For maintaining current flow in said device, and a closed secondary in inductive relation therewith to prolong. the discharge of energy from said reactive means.

In witness whereof, I have hereunto set my hand this 18th day of May, 1966.

CHARLES P. STELNMETA. Witnesses:

BENJAMIN B. HULL, HELEN ()Rronn. 

